Integumentary System I

Question 1

What is the largest system of the body?

Answer 1

The integumentary system

Question 2

How much of our body weight is comprised of skin?

Answer 2

16%

Question 3

How thick is our skin?

Answer 3

0.5-4mm thick

Question 4

How large is the surface area of our skin?

Answer 4

2m^2

Question 5

What is the integumentary system divided into?

Answer 5

1. Cutaneous Membrane (skin)

2. Accessory structures

Question 6

What is the integumentary system connected to?

Answer 6

1. CVS

2. NVS

Question 7

What are the functions of skin?

Answer 7

• physical protection from environmental hazards
• storage of lipids
• thermoregulation
• excretion
• sensory info
• production of melanin & keratin
• synthesis of vit D
• coordination of immune response

Question 8

What does the cutaneous membrane comprise of?

Answer 8

1. Outer Epidermis (Superficial Epithelium)

2. Inner Dermis

Question 9

What do accessory structures comprise of?

Answer 9

1. Hair Follicles
2. Exocrine Glands
3. Nails

Question 10

Is there an additional layer beneath the cutaneous membrane?

Answer 10

Yes, it is the Superficial Fascia called the Hypodermis (Subcutaneous Layer)

Question 11

What is the clinical significance of the Hypodermis?

Answer 11

It is the location for hypodermic injections as the hypodermis has blood vessels

Question 12

What is the Hypodermis made up of?

Answer 12

LOOSE connective tissue

Question 13

What is the function of the Epidermis?

Answer 13

• Protects dermis
• Prevents water loss & entry of pathogens
• Synthesises Vit D
• Contain Sensory Receptors

Question 14

What is the function of the Dermis?

Answer 14

• (Papillary) Nourishes & supports epidermis
• (Reticular) Thermoregulation via Blood Vessels
• (Reticular) Contain Sensory Receptors which detect vibration additionally

Question 15

What is the Epidermis made up of?

Answer 15

Epithelial Tissues

Question 16

What is the Dermis made up of?

Answer 16

Connective Tissues

Question 17

Where do accessory structures originate?

Answer 17

Dermis

Question 18

Why is the Epidermis a Stratified Squamous Epithelium?

Answer 18

Helps diffuse nutrients and oxygen from the capillaries in the dermis

Question 19

What are the cells of the Epidermis?

Answer 19

Keratinocytes are the most abundant

Question 20

What is Thin Skin?

Answer 20

It covers MOST of the body and contains 4 layers of keratinocytes (x Stratum Lucidum)

Question 21

What is Thick Skin?

Answer 21

It covers the palms of then hands and the soles of the feet and contains 5 layers of keratinocytes

Question 22

What are the strata of Thick Skin?

Answer 22

1. Stratum Corneum
2. Stratum Lucidum
3. Stratum Granulosum
4. Stratum Spinosum
5. Stratum Basale

Question 23

How is the Stratum Basale attached to the basement membrane?

Answer 23

By hemidesmosomes

Question 24

What are the functions of the Stratum Basale?

Answer 24

1. Forms strong bond between epidermis & dermis

2. Contains Epidermal Ridges (Fingerprints)

Question 25

Where is the Stratum Basale?

Answer 25

Next to Dermal Papillae in Dermis

Question 26

What are the cells of the Stratum Basale?

Answer 26

1. Basal cells (germinative cells)

Question 27

What are the functions of the Dermal Papillae?

Answer 27

1. Strengthen attachment between Epidermis & Dermis | 2. Increase area of Basement Membrane

Question 28

What are the Specialised Cells of the Stratum Basale?

Answer 28

1. Tactile Cells (Merkel Cells) - with sensory nerve endings, respond to touch, found in hairless skins 2. Melanocytes which contain the pigment melanin

Question 29

What is the Stratum Spinosum produced by?

Answer 29

Division of the Stratum Basale

Question 30

How many layers of keratinocytes bound by desmosomes are there in the Stratum Spinosum?

Answer 30

8-10

Question 31

Why is the Stratum Spinosum called the 'spiny layer'?

Answer 31

Cells appear spiny

Question 32

What cells make up the Stratum Spinosum?

Answer 32

Dendritic (Langerhans) cells that are active in immune response

Question 33

What is characteristic of the cells in the Stratum Spinosum?

Answer 33

They continue dividing to increase the thickness of the epithelium

Question 34

How many layers of keratinocytes are there in the Stratum Granulosum?

Answer 34

3-5

Question 35

What is characteristic of the cells in the Stratum Granulosum?

Answer 35

Most cells stop dividing and produce Keratin (tough fibrous protein that makes up hair and nails) and Keratohyalin (dense granules that cross-link keratin). They die upon producing the proteins.

Question 36

Where is the Stratum Lucidum only found?

Answer 36

In thick skin

Question 37

What is the function of the Stratum Lucidum?

Answer 37

Covers the Stratum Granulosum

Question 38

What is the Stratum Corneum?

Answer 38

Exposed surface of skin that is water resistant

Question 39

How many layers of keratinocytes are there in the Stratum Corneum?

Answer 39

15-30

Question 40

How long does it take for new cells to move from the Basal layer to the Horn layer?

Answer 40

7-10 days

Question 41

When do exposed cells shed?

Answer 41

After 2 weeks

Question 42

What is Keratinisation?

Answer 42

Formation of a layer of dead, protective cells filled with keratin (formation of many tough, waterproof layers)

Question 43

Where does Keratinisation occur?

Answer 43

On all exposed skin surfaces except the eye

Question 44

What is Acne?

Answer 44

Disorder in the keratinisation of the skin that leads to the presence of comedones (blackheads & whiteheads)

Question 45

How is water lost from the skin?

Answer 45

1. Insensible perspiration (Diffusion of water across the Stratum Corneum before it evaporates from the skin) 2. Sensible perspiration (Water excreted by sweat glands in hot environment or during exercise)

Question 46

What is Epidermal Growth Factor (EGF)?

Answer 46

Powerful peptide growth factor used in labs for growth of skin grafts

Question 47

How is EGF produced?

Answer 47

By glands (salivary & duodenum)

Question 48

What are the functions of EGF?

Answer 48

- Promote division of germinative cells - Accelerate keratin production - Stimulate epidermal repair - Stimulate glandular secretion